Cerebral perfusion pressure and cerebral tissue oxygen tension in a patient during cardiopulmonary resuscitation.

Abstract

To report on the effects of cardiopulmonary resuscitation (CPR) instituted immediately after a cardiac arrest on cerebral perfusion pressure (CPP) and cerebral tissue oxygen tension (PbrO(2)). Case report. ICU of a university hospital. A head-injured 17-year-old man submitted to multimodal neurological monitoring underwent sudden cardiac arrest and successful CPR. External chest compression, 100% oxygen ventilation, volume expansion and standard ACLS protocols. Heart rate, ECG, mean arterial blood pressure (MABP), ETCO(2), PaO(2), intracranial pressure (ICP), CPP and PbrO(2) were continuously monitored during CPR and data recorded at 15-s intervals by a dedicated personal computer. At the onset of the cardiac arrest, PbrO(2) decreased to zero. The institution of CPR resulted in a progressive increase of MABP, CPP and PbrO(2). Assuming, on the basis of previous experimental and clinical reports, 8 mmHg PbrO(2) as a possible ischaemic/hypoxic threshold value, during the first 6.5 min of CPR, PbrO(2) values were below this threshold (range 0-7 mmHg) and CPP values were <25 mmHg for 81.5% of the time. In the following 5.5 min, more efficient CPR generated CPP values >25 mmHg for 77.3% of the time. These values were associated with a PbrO(2) >8 mmHg (range 8-28 mmHg) at all times. In the clinical setting of a witnessed cardiac arrest, immediate institution of CPR can be effective in generating PbrO(2) values above a supposed ischaemic/hypoxic threshold when CPP is >25 mmHg. PbrO(2) monitoring by the Licox system is sensitive and reliable, even at low values, and can be suitable for evaluating cerebral oxygenation during experimental CPR.